@dsrromero I’m building up a linear bearing platform right now. In the beginning, it’ll be “surge” fore/aft only. We’ll see how it turns out.
I’m thinking about two different setups now - parallel rails and a MONORAIL! setup https://imgur.com/a/Rbc70ug . The parallel would be without roll. The MONORAIL one would use the linear bearing’s 5-10 deg of pitch, but I’d have it above the pivot above ground level to stimulate real world roll when spiriting ( like this guy has https://www.cykeel.com/ as he rocks the way you ride)
The MP1 is actually a long radius swing foreaft (with foreaft+pitch). When trying it, the foreaft did most of the work. This is partially because the motion is undampened, running on efficient rollers. In roll, you only need a few degrees and likely wouldn’t exceed the line between your pedal inner edge, inner thigh, and the top tube (0-10cm lateral motion depending at top tube height). On the MP1, this is dampened I believe with a rubber flexy thing.
A lot of what the platform is doing is digesting your bikes normal flex. You’ll note that you do not get as beat up on a rigid spin bike as you do on your trainer. As you pedal, your bike frame flexes, and it ends up moving the saddle around on your backside. The platform tries to eat some of this motion up from the bottom. If someone came out with a saddle with some roll and surge shear, it might do the same thing as a platform and be 1/5th the cost - MIPS for saddles (maybe just wear winter over-tights or buy a crappy saddle cover)